On another side is a grassy field, where a school sports tournament is taking place. Barefoot boys play rugby, the national passion, as parents and other children noisily offer support on one side of the field. A handful of dignitaries and a brass band take shelter under a marquee on the other.
This year the field, known as Pangai Lahi, has become the focus of a battle of a different kind - protests, huge by Tongan standards, aimed at ending the archipelago's semi-feudal system of government.
Under banners reading "Enough Lies, Time for Truth" and "Unity and Solidarity for Freedom" thousands have sung, chanted and prayed in the shadow of the palace.
Today the 30 member parliament comprises 12 ministers appointed by 87-year old King Taufa'ahau Tupou IV, nine representatives elected by 33 nobles and just nine representatives elected by popular vote.
Veteran leading democracy campaigner and MP 'Akilisi Pohiva says momentum is building for change.
"It will happen within the next two years," he says firmly. Demonstrations this year culminated with a six week public service strike which ended in September when the government capitulated and granted pay rises of between 60 and 80 percent. Pohiva says this made people realise for the first time they could take on the government and win.
"That was the first time for the people to be united and the most important outcome of that strike was the strength and the power is not the hands of the monarchy but in the hands of the people," he says.
The king is an increasingly remote figure in the kingdom of around 100,000 people spread over 171 islands lying 2,000 km north of Auckland. He is mainly wheelchair-bound and has spent long periods this year in New Zealand receiving medical treatment and his Auckland home has become a focus of protest for expatriate Tongans.
When he first came to power in 1965 the imposing Taufa'ahau - once famous as the world's heaviest monarch at over 200 kg (440 pounds) - was credited for his modernising drive.
But now the key figure is his son Crown Prince Tupouto'a, who lives in a huge mansion on a large estate outside Nuku'alofa. The Crown Prince is a controversial figure due to his control of the privatised monopoly electricity company, the country's brewery, an airline and a telecommunications company.
The power company was a focus of a protest in May over rising power prices and extravagant salaries paid to top executives in a country where many public servants earn as little as 3,000 or 4,000 pa'anga (1,500 - 2,000 US dollars) a year.
Public protest reached a peak with a public service strike with estimates of between 10,000 and 20,000 taking part in one march.
Pohiva says the democracy movement is about to hand to the government a set of constitutional amendments which if adopted would usher in a democratic state where parliament would be popularly elected.
The prime minister - currently the king's youngest son 'Ulukalala Lavaka Ata - would be chosen by MPs rather than the monarch and in turn the prime minister would pick the cabinet.
The government has been given a December 5 deadline to accept the changes or new protest action - which Pohiva did not want to specify - will be launched.
He says he hopes the transition to democracy will be peaceful but warns that history does not give cause for optimism.
Another leading figure in the democracy movement is Clive Edwards, once the kingdom's police minister who was known as a royal "enforcer". Since being sacked last year, he has embraced the democracy movement and his former foes.
He says the patience of the people - who have traditionally been respectful of authority and the rigid class system - is wearing thin.
Tonga is the last kingdom in the Pacific and one of the last semi-feudal societies anywhere. Publisher and journalist Pesi Fonua, who runs the respected online news site Matangi Tonga, points to a failed attempt by the government to clamp down on the press two years ago as a key moment in the drive for change.
Freedom of expression and of the press is contained in the Tongan constitution and the courts last year threw out new government laws which had forced the closure of three increasingly outspoken Tongan newspapers.
"The move by the government to control the media in 2003 was probably the best thing that ever happened to the media in Tonga because prior to that even though we had press freedom and freedom of speech in the constitution, we took it for granted and the public took it for granted," Fonua said.
"We started to campaign against (government control) and talking about it and somehow then I think the people started to realise what it means to have freedom of speech, what it really means."